1.20pm 12 Sept 1862 – turn 17

All has become clear over the last couple of hours – the enemy have indeed split their forces into three columns and have crossed the Potomac at Shepherdstown and Falling Waters with the third column attempting to cross at Williamsport. My decision to send cavalry to reconnoitre Williamsport has paid off because they are in a position to delay the Rebels and buy time for my infantry to come up.

The strategic situation at 1.20pm - my forces are attempting to isolate the portion of enemy troops advancing from the south.

Lee’s audacious plan to divide his army in the face of superior enemy numbers will either turn out to be brilliant masterstroke or a total disaster for the Confederates. My aim now has to be to prevent Lee from reuniting his army and to this end I now have Hooker’s corps deployed astride the Hagerstown-Sharpsburg pike at Jones Crossroads isolating the enemy force advancing from Sharpsburg.

The battlefield at Jones Crossroads - an artillery exchange has begun but I don't expect the Rebels to attack, they are more likely to try to slip away to their left to attempt a link up with the troops coming from the direction of Falling Waters.

Mansfield and Sumner are moving up fast into the rear of the enemy and there is a good chance we will trap and destroy a good part of the Rebel force!